common-types/src/main/java/org/apache/falcon/Pair.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.falcon;

import java.io.Serializable;

/**
 * Simple pair class to hold a pair of object of specific class.
 * @param <A> - First element in pair.
 * @param <B> - Second element in pair
 */
public class Pair<A, B> implements Serializable {

    private static final long serialVersionUID = 1L;

    //SUSPEND CHECKSTYLE CHECK VisibilityModifierCheck
    public final A first;
    public final B second;
    //RESUME CHECKSTYLE CHECK VisibilityModifierCheck

    public Pair(A fst, B snd) {
        this.first = fst;
        this.second = snd;
    }

    public static <A, B> Pair<A, B> of(A a, B b) {
        return new Pair<A, B>(a, b);
    }

    @Override
    public String toString() {
        return "(" + first + "," + second + ")";
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        Pair pair = (Pair) o;

        if (first != null ? !first.equals(pair.first) : pair.first != null) {
            return false;
        }
        if (second != null ? !second.equals(pair.second) : pair.second != null) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        int result = first != null ? first.hashCode() : 0;
        result = 31 * result + (second != null ? second.hashCode() : 0);
        return result;
    }
}